This study, done in collaboration with investigators in the Division of Cancer Etiology, was designed to detect the effects of cancer and its treatment on childhood patients who survived to adulthood as well as to detect as any effects that might have been transmitted to offspring. Specific issues for investigation were the occurrence of subsequent primary cancers, quality of life, late morbidity other than cancer, infertility among the cases, and cancer and birth defects among offspring. Cases were selected from 5 U.S. cancer registries that had a histologically confirmed malignant neoplasm or brain tumor diagnosed under age 20 years, between 1945 and 1974, who survived at least 5 years after diagnosis, and who reached the age of 21 years. Up to 2 sibling controls were selected for each case with sequential priority given to full blood relationship, same sex, closest in age. Interviewer administered questionnaires were obtained for 2,305 (91%) of cases and 3,299 (77%) of controls. Preliminary observations indicate that cancer occurred in 0.34% of offspring of cases, versus 0.21% of offspring of controls. These two rates were not significantly different from each other or from general population expectations. One or more major birth defects occurred in 8.3% of case-children and 7.4% of control children; these results were not signigicantly different. The quality of life issues investigated in this study included graduation from high school, age at graduation, marital status, parental status, and health interference with taking a job or holding a job. The percentages who graduated from high school were similar for cases and controls as were the ages at graduation. When compared with controls, higher percentages of cases reported they never married, didn't marry because of a health problem, married but had no children, and had health problems that interfered with vocational status.